I am pleased to report that, having replaced the original voltage stabilizer in my 1983 jetta gasser cluster with an $0.75 Fairchild LM7810, my tach works excellently! No wiring mods at all in my 1984 jetta. I modified the tach board and nothing else.

I'm sure i still need to tweak it, which will happen after i fasten a piezo pickup to my #1 injector line and hook up a silly scope.

PM me if you need to replace your voltage stabilizer. The $28 charged by mk1autohaus is highway robbery. $5 CONUS shipped. You'll need a stack of 7 or 8 #4 brass washers and a #4 1/2" wood screw because the LM7810 mounts up-side-down vs. how the original part was mounted. I have exactly 3 extras. heck, I'll even throw in a brass #4 1/2" screw .

If you are stuck there, I question whether or not you should be attempting the conversion.

De-solder the two wires noting their color/location. Lift off the circuit board.

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Has anybody modified this board to make it work? the circuit is different, but not too much different than the other boards mentioned in this post. Still cant figure out how to covert it though. I have a schematic drawn out if anyone wants to see that but it isn't the prettiest drawing

I just got a mk1 tach swapped over in my '79 rabbit. Along with replacing the appropriate tachometer components I also had to add the W-terminal to the alt also as the alt didn't have one. It works great.

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Guys any one have the complete guide with pictures, I have and M-TDI, and need to put the petrol rpm gauge in my cluster but i´ve been told that is needed to change somethings to make it work with the w terminal, and them i was sent here to this post, any help please?

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You'll have to trace out your board (front and back) but they are all basically the same schematic and require the same replacement items.

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Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California